jaytee
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Posts posted by jaytee
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Just wired this up this afternoon. Seems to work like a charm!
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My understanding is that only the Lead Engine is supported by super-poly mode. So four voices only, but you get super flexible voices.
You can do six voices in the Multi Engine, but those are paraphonic voices (only one filter per three oscillators), and as above, every three voices will switch from R to L.
If you want absolute maximum polyphony, you could get 24 voices by using four instances of the same Multi Engine patch on different channels with some external MIDI trickery (software or hardware that can switch to the next channel every six notes), but I would suggest that if you need 24 voices, you're starting to get well outside the strengths of the SID chip.
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This is a hardware limitation. Each SID has a separate output, directly routed to either L or R, so voices that only sound from one SID will be panned by necessity. Best way to adjust this is in a DAW or on your mixer. You could wire up a passive mixer inside your MBSID that allows you to adjust pan, but it's a lot of work for not a lot of payoff.
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On December 4, 2016 at 3:29 PM, ilmenator said:
Why is everybody so obsessed with these rocker switches? There are many panel mount / snap in alternatives out there. Panel mount means no stress on the PCB...
I ask a couple questions about a part and now I'm "obsessed."
Getting the part intended by the designer, in this case, saves me from doing extra work: shopping through digikey's enormous selection of switches, checking datasheets to make sure it's a good fit for the available space, re-jiggering the back panel cutout. It's all minor stuff, but not as minor as spending two minutes to ask around a forum for spare parts (which paid off, I might add, as a friendly member sent me the part for only the cost of shipping).
In other cases, the effort to use the intended part might *not* be worth it. For instance, I won't be using the C64-style DIN7 plug for power. I'll have to re-jigger the back panel to fit my panel-mount choice, but it saves me from having to assemble a power supply with a DIN plug.
Do these tiny calculations of worthwhile effort make me obsessed? Perhaps. But I'm building myself a synthesizer; why shouldn't I make it to my very own specifications?
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4 hours ago, TK. said:
I'm in contact with the designer.
The good news: he plans a public release of all sources, which means that it will be possible to change the HW interface so that it can be directly connected to the core w/o need for serial shift registers!
It might even be possible to use a bigger FPGA for the emulation of 8 SIDs, all connected to a single SPI which will be the best way how to control the SIDs from a MBHP_CORE_STM32F4 module.
Best Regards, Thorsten.
...holy shit!
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I mean that half the community has started projects that never got off the ground in any meaningful way.
I don't expect that pointing out the terms of the TAPR will result in any previous projects getting a public release. Rather, I just think that going forward, it's important that folks understand what license all this IP falls under, and that it does indicate that documentation should be shared.
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The digital section is supposed to be cycle-for-cycle accurate once all is said and done. The analog emulation will be tougher, but the sound demos are very encouraging.
The plus side is that you could theoretically "fix" any of your least favorite SID issues. Want to use the volume envelope without the infamous bug? No problem. Want to boost the resonance a bit to get a really nice acid bassline? Do it.
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Hawkeye nailed it. Announcing a project to the community doesn't obligate someone to follow through; if that were the case, half the MB community would be deep in unfinished project debt! ;) Rather, it would just be nice if documentation were more freely shared, as the TAPR license indicates, instead of hoarded.
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I don't have feedback pots installed, so I can't comment on those. On my sammichSID, the external-ins are tied to ground by default (via switching jack) and there's very little noise.
As for the volume levels of patches, I can't really say either way without hearing an example....but it's certainly possible to set up patches to have very different volume levels...
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As far as I know, the software is the same for different SID chips; the different hex files just specify certain default settings for the filters to save you the trouble of setting them.
The Bankstick configuration shouldn't matter either. Patches designed for different SID revisions won't sound quite right on the "wrong" chip, but they're not incompatible. They can be assigned to any core from any Bankstick.
Hopefully @TK. can come confirm what I'm telling you—only about 90% confident on my answers, having read the MB SID documentation a couple dozen times but not having finished a multi-core SID project yet—but I'm pretty sure you're overthinking things. I can definitely say that many folks have completed MB SID projects with mixed SIDs before, so it is 100% possible, no problem.
edit: As for the difference between SID revisions... I personally prefer the 8580/6582. Between the additional waveforms, the noise reduction and the improved filter, it makes the most sense to me for building a musical instrument. That said, it seems like folks who grew up on C64 music prefer the 6581; I'll certainly admit that despite its flaws, the 6581 does have a really nice sound.
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I don't think I'd build a new MIDIbox specifically to put these in, but I'll happily grab a full set to have when real replacement SIDs finally become impossible to find.
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Thank you @ChinMuzik. I'm just waiting for the package to arrive now.
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Nope, not even close. The proper switches are 90° mount.
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One last ditch effort to find this apparently unobtanium switch. Anyone have a spare they want to get rid of? Anyone have a gutted C64 with in-tact switch? Anyone know of a replacement part?
Fingers crossed. Thanks.
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On November 17, 2016 at 5:39 PM, verpeiler said:
I'm looking for a rocker switch as well. You can find some at eBay from time to time (search for c64 switch, I think they will fit but I'm not 100% sure). Currently a seller in Germany has some of them, but 9 Euro for a used part...
Have you seen Hawkeye's great Building the MB-6582 Control Surface - Photo Tutorial ? It's very helpful and contains part numbers.
BTW: For the base to cs connections I would recommend to just follow Wilba's instructions and use the stiffy flat flex cable. It's more than sufficient. Once you are done you will open the case maybe 5 times. A detachable solution is always nice but not worth the effort.
I have Hawkeye's tutorial on a permanent tab on my computer browser ;)
I can't seem to find anyone in North America selling those switches, unfortunately. I would honestly pay $10 or so for the right switch (fuck it!) but $10 plus international shipping is getting ridiculous. Unless someone has a spare or a suitable replacement is found, I'm probably gonna find something to panel mount, as much as I hate it.
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Is there any way we can just get the board files released to the MIDIbox community? Or even just sent to Tim at the MIDIbox Shop for occasional small runs, a la the MB-6582? It feels insane to have this many people waiting for years on the next run of kits.
I don't want to diminish the hard work that @nILS and @Wilba put into these designs; quite the opposite, actually. I admire the designs greatly and don't think I would be capable of creating something on the same level. I totally understand why they would have wanted to keep the board designs to themselves while sammich kits were in production—demand was enormous when these kits were originally announced and keeping the board designs private ensured that nobody shady would take advantage of the situation and begin selling kits themselves. But circumstances have changed, and it seems like we're back to the normal state of MIDIbox affairs: just a few DIYers who want a fun project for themselves.
Now that the kits are long out of production, what purpose does keeping the design files private serve?
Also—and I mean this as a sincere, curious question, with no intention of being accusatory or inflammatory—the TAPR license that all MIDIbox designs fall under seems to imply that any derivative designs are to be "open" as well, at least with regard to sharing documentation. So I'm left feeling confused as to why certain MB designs end up as proprietary. Obviously, the sammiches were produced with @TK.'s explicit approval (aka word of God), so there's no suspicion on my part of wrongdoing—rather, I am just hoping for a clarification on the rules of the TAPR.
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Ah, I see what you're talking about. I actually hadn't even considered the board-to-board connections yet; I was still stuck on the headers for the panel-mount stuff on the back (mix out, expansion port, etc). But it is good to know that the CS board will fit them, if barely.
Probably going to order more parts tomorrow!
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Thanks @jjonas! This is very helpful.
With the knobs, I always just worry that I'm misinterpreting a measurement, like that the diameter is the inside of the knurls instead of the outside, or that they won't cover the threaded section of the pot... I think I need to just bite the bullet and buy some, and if they fit, they fit, and if they don't, I learned something.
As for the connectors.... Hmm. At the very least, it's encouraging to know that they come in "kits." Previously I was trying to look up the right parts on Mouser/Digikey and I couldn't make heads or tails of what bitsies went with which bobbinses. Hopefully someone else can chime in about whether the cheaper-but-taller connectors fit in the Pac-Tec....
Or I could just skip the Pac-Tec altogether. I know someone who makes sheet metal + wood cheeked enclosures that look really nice. They've made MB-6582 cases in the past I know. I haven't inquired about price (I'm sure it ain't cheap) but the Pac-Tec seems like a little bit of a pain in many ways (space mostly). I only figured I'd go with it because I found a source of cheap panels.
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Thanks @Janis1279.
I will be using a Recom switching regulator to get 5V. It comes well-recommended by other members of the forum, and those that have installed it report no heat issues or switching noise. I am not worried about this aspect of the build at all.
Re: feedback pots. Thank you for confirming the necessary resistance. Do you know if log or linear is better? Can you recommend a specific pot/knob combination? Have you noticed any noise issues with the feedback pots as opposed to tying the inputs to ground?
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Making a big Mouser order for the MB-6582 parts I couldn't source from Tayda. I have a few questions about the BOM.
- Is there anywhere to source the necessary rocker-style power switches? All I can find is a couple references to Wilba selling them from a larger batch. I used the photo on the old group buy wiki page to figure out what part it was, but can't find any place to purchase it. Is there another suitable part? Does anyone on the board have these? Should I just go with some other (probably panel-mount) switch and adjust the rear panel design as needed? I think I'm going to do that with the power jack anyway, since I'm gonna run it from a single 12V supply and want to use a standard jack instead of the 7-pin DIN jack.
EDIT:
I seem to have found a switch that matches. First of all, it looks like the switch that Wilba was supplying is the R8011L from Salem (caveat, this is my best guess based on the image on the group buy wiki page). As far as I can tell, this switch (E201J1AV2BE2 from C&K) seems to be a close match. Only difference I can find is that the rocker sticks out an extra fraction of a millimeter. Not cheap, unfortunately. I'll probably buy one and give it a shot unless anyone points out that I've missed some crucial detail that makes it incompatible. I'll report back whether it works or not. Hopefully this is a help to anyone else looking for this rare part.Actually, upon closer inspection, I think the switch that Wilba supplied was the R8017L from Salecom. Ever so slightly different. C&K lists a matching part in their datasheet (E201J1V5BE2 ), but it doesn't seem to be for sale anywhere. Back to the drawing board.- The feedback pots aren't on the BOM. I think they're supposed to be 500k dual-gang pots, right? Log or linear taper (I think log, right)? Can anyone suggest a matching pot/knob combo? I know that the pots probably aren't hard to find, but I feel totally inept at match knobs to pot shafts.
- Speaking of the feedback pots, how useful do folks find them? I'm considering leaving them out entirely. Despite seeing successful installs from other folks, I worry about noise coming in on the audio-in pin, and about eventually blowing the SID filters, which I've heard the audio-in can do. I'm using 8580/6582 SIDs, if it makes any difference.
- There's nothing in the BOM about securing the base PCB to the Pac-Tec case. Are the screws included with the PT-10 sufficient or are those only to close the case? I can't really tell from the PT-10 data sheet.
- Can anyone give me a quick primer on crimp pins/female connectors for the headers on the base PCB? I promise I've googled this, but I must not be searching for the right things. It seems like a lot of DIY stuff assumes knowledge on what pieces and parts one needs to buy to assemble female connectors for headers, but this will be my first time not just soldering wires directly to the board in lieu of headers altogether (trying to do this right!).
- Speaking of connectors, can anyone offer Mouser part numbers for the correct LCD connector. I have a better idea how to assemble this piece at least, thanks to the guide to MIDIbox display cables, but I just want to be sure I'm getting the right part; again, first time working with these types of connectors.
-Any other parts that aren't on the BOM that I should pick up? Even just basic stuff that most folks would already have in their workshop. Only things I've come up with are shunts and a few machine-pin female headers (for SID capacitors and LED resistors).
Sorry, I know this is a ton of questions about stuff that most folks here (and elsewhere in the DIY world) take for granted as simple matters. Just looking for a little guidance before I drop a bunch of money on parts. Better to ask these questions now than after parts arrive and I get the wrong stuff.
As a post-script, let me just say that I do not recommend buying IC sockets from Tayda, or at the very least, not the 28-pin wide sockets (i.e. SID sockets). On two separate sockets, a pin came loose while placing it into the PCB and the wipers slid upward. Really poor quality.
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@jjonas, the last time that page was updated was before the most recent batch of stock was put up.
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I received mine last week.
If you haven't yet, try emailing Tim at the email address listed in your order confirmation. He got back to me pretty quickly that way. It sounds like he's been traveling and busy with non-MIDIbox stuff.
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Can you give a quick explanation on how your proposed solution works? I took a look at that data sheet but can't really figure out what it does.
either way, definitely interested to hear if it works!
MB-6582 board set availability (possible bulk order?)
in MIDIbox SID
Posted
@Molom